title: Evolving genetic code.
abstract: In 1985, we reported that a bacterium, Mycoplasma capricolum, used a deviant genetic code, namely UGA, a "universal" stop codon, was read as tryptophan. This finding, together with the deviant nuclear genetic codes in not a few organisms and a number of mitochondria, shows that the genetic code is not universal, and is in a state of evolution. To account for the changes in codon meanings, we proposed the codon capture theory stating that all the code changes are non-disruptive without accompanied changes of amino acid sequences of proteins. Supporting evidence for the theory is presented in this review. A possible evolutionary process from the ancient to the present-day genetic code is also discussed.
authors.affiliation: Kochi University of Technology, Department of Environmental System Engineering, Kochi, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ohama
authors.forename: Yuji
authors.initials: Y
authors.lastname: Inagaki
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Bessho
authors.forename: Syozo
authors.initials: S
authors.lastname: Osawa
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003062:Codon; D019143:Evolution, Molecular; D005798:Genes, Bacterial; D005815:Genetic Code; D045623:Mycoplasma capricolum / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D003062:Codon; D012333:RNA, Messenger